package cn.edu.hznu.util.concurrent;

public class WaitAndNotifyTest {

	// state==1表示线程1开始打印，state==2表示线程2开始打印
	private static int state = 1;

	private static int num1 = 1;
	private static int num2 = 2;

	public static void main(String[] args) {
		final WaitAndNotifyTest t = new WaitAndNotifyTest();
		new Thread(new Runnable() {
			@Override
			public void run() {
				while (num1 < 100) {
					// 两个线程都用t对象作为锁，保证每个交替期间只有一个线程在打印
					synchronized (t) {
						// 如果state!=1, 说明此时尚未轮到线程1打印, 线程1将调用t的wait()方法, 直到下次被唤醒
						if (state != 1) {
							try {
								t.wait();
							} catch (InterruptedException e) {
								e.printStackTrace();
							}
						}
						// 当state=1时, 轮到线程1打印5次数字
						for (int j = 0; j < 5; j++) {
							System.out.println("Thread 1 >>>>> " + num1);
							num1 += 2;
						}
						// 线程1打印完成后, 将state赋值为2, 表示接下来将轮到线程2打印
						state = 2;
						// notifyAll()方法唤醒在t上wait的线程2, 同时线程1将退出同步代码块, 释放t锁
						t.notifyAll();
					}
				}
			}
		}).start();

		new Thread(new Runnable() {
			@Override
			public void run() {
				while (num2 < 100) {
					synchronized (t) {
						if (state != 2) {
							try {
								t.wait();
							} catch (InterruptedException e) {
								e.printStackTrace();
							}
						}
						for (int j = 0; j < 5; j++) {
							System.out.println("Thread 2 >>>>>>> " + num2);
							num2 += 2;
						}
						state = 1;
						t.notifyAll();
					}
				}
			}
		}).start();
	}
}
